1. Field of the Invention
The present invention relates generally to magnetoresistive read sensors for hard-disk drives and, more particularly, to bottom-synthetic-spin-valve giant-magnetoresistive read sensors.
2. Description of the Related Art
In conventional bottom-synthetic-spin-valve (BSSV) giant-magnetoresistive (GMR) read sensors, the effective bit spacing and magnetic readback pulse width (and resolution) are correlated with the shield-to-shield spacing of the GMR read sensor. During readback, the shields filter out flux from the transition regions between the bits so as to reduce the low spatial frequency while high spatial frequencies are enhanced. Thus, the shields help achieve high signal-to-noise ratios at detection.
Each generation of GMR read sensors has utilized proportionate reductions in the shield-to-shield spacing to achieve the desired discrimination of bits having a smaller bit spacing. However, further shrinkage of the shield-to-shield spacing is limited by a minimum size required for the GMR read sensor and a minimum size for insulative gaps to prevent electrical conduction between the GMR read sensor and the shields. Minimum shield-to-shield spacings of approximately 675 Angstroms have been achieved using conventional technology.